49 lines
2.0 KiB
JavaScript
49 lines
2.0 KiB
JavaScript
export const processLazyPreloader = (swiper, imageEl) => {
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if (!swiper || swiper.destroyed || !swiper.params) return;
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const slideSelector = () => swiper.isElement ? `swiper-slide` : `.${swiper.params.slideClass}`;
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const slideEl = imageEl.closest(slideSelector());
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if (slideEl) {
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const lazyEl = slideEl.querySelector(`.${swiper.params.lazyPreloaderClass}`);
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if (lazyEl) lazyEl.remove();
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}
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};
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const unlazy = (swiper, index) => {
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if (!swiper.slides[index]) return;
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const imageEl = swiper.slides[index].querySelector('[loading="lazy"]');
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if (imageEl) imageEl.removeAttribute('loading');
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};
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export const preload = swiper => {
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if (!swiper || swiper.destroyed || !swiper.params) return;
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let amount = swiper.params.lazyPreloadPrevNext;
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const len = swiper.slides.length;
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if (!len || !amount || amount < 0) return;
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amount = Math.min(amount, len);
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const slidesPerView = swiper.params.slidesPerView === 'auto' ? swiper.slidesPerViewDynamic() : Math.ceil(swiper.params.slidesPerView);
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const activeIndex = swiper.activeIndex;
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if (swiper.params.grid && swiper.params.grid.rows > 1) {
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const activeColumn = activeIndex;
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const preloadColumns = [activeColumn - amount];
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preloadColumns.push(...Array.from({
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length: amount
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}).map((_, i) => {
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return activeColumn + slidesPerView + i;
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}));
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swiper.slides.forEach((slideEl, i) => {
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if (preloadColumns.includes(slideEl.column)) unlazy(swiper, i);
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});
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return;
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}
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const slideIndexLastInView = activeIndex + slidesPerView - 1;
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if (swiper.params.rewind || swiper.params.loop) {
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for (let i = activeIndex - amount; i <= slideIndexLastInView + amount; i += 1) {
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const realIndex = (i % len + len) % len;
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if (realIndex < activeIndex || realIndex > slideIndexLastInView) unlazy(swiper, realIndex);
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}
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} else {
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for (let i = Math.max(activeIndex - amount, 0); i <= Math.min(slideIndexLastInView + amount, len - 1); i += 1) {
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if (i !== activeIndex && (i > slideIndexLastInView || i < activeIndex)) {
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unlazy(swiper, i);
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}
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}
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}
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}; |